Independent redundant clutchless retractor

ABSTRACT

A safety belt retractor having a pair of actuating means which are independently responsive or condition sensitive to acceleration of webbing withdrawal and to ominidirectional acceleration or deceleration of the vehicle. The condition sensed first actuates a pilot pawl and the pilot pawl mechanically and positively engages means which drive the locking pawl to prevent webbing withdrawal from the webbing drum or reel. The pilot pawl is cam activated by the relative movement between a flywheel and the shaft of the drum or reel as is sensed by sudden withdrawal force on the webbing, or upon relative delay of rotation or lag in the flywheel consequent to inertial displacement of a pendulum and following pawl to ratchet engagement with the flywheel. The locking force of pilot pawl to drive the ratchet and the locking force to drive the pendulum pawl to the flywheel ratchet is minimal and the locking thrust of the lock pawl to the ratchet drum is by emergency stress felt on the harness or webbing and conveyed into the retractor frame and vehicle. The pendulum is miniaturized and the actuator mechanism is predominantly formed from precision molded resin parts.

The present invention is an independent redundant and compact clutchlessretractor in which positive drive engagement of pawls to ratchets (whichare concentrically and nestably disposed in respect to each other) onthe shaft results in a motion coordinated movement of the lock pawl toratchet drum. This achieves a positive locking of the retractor againstwithdrawal of webbing when omnidirectional inertial imbalance is felt inthe movement or position of the vehicle in which the retractor is placedor when sudden withdrawal accelerates the relative speed of theretractor shaft to flywheel. The relative lag of the flywheel is sensedby a shaft driven pilot pawl and the pilot pawl engages a lock driveinner ratchet drum which reacts positively to tilt the lock pawl intoengagement with the ratchet flanges on the reel or drum and therebylocks the webbing. As the sensed condition abates and the tension on thewebbing is relaxed surplus webbing is spooled on the drum by theretractor. The locking against withdrawal is achieved in a positivemanner without use of a clutch having slippage and the coordination ofpawl to teeth in drive of the pawl bar assures repetitive pawl entry tothe ratchet tooth in contrast to chance bounce of pawl to tooth whichoccurs in prior known clutch type structures. This is the consequence ofgeometry in which the drum flange ratchet has the same number of teethas the internal ratchet which drives the pawl bar.

The Prior Art

In the prior art two distinct types of inertial retractors have beenwell developed. The pendulum type vehicle sensitive retractor in eitherunidirectional or omnidirectional style are well known and generallycomprise structures in which the displacement of a mass or pendulum fromnormal vertical hanging position causes a movement of a pawl and thepawl engages a ratchet driven by the drum or reel of the retractor.These are known as vehicle-sensitive retractors. A second type ofinertial retractor relies upon relative imbalance as between the drivenshaft of the retractor drum on withdrawal of webbing and an inertialmass or flywheel so that as displacement occurs consequent to therelative imbalance, a clutch tilts a pawl or locking lug intointerference relation with teeth on a ratchet wheel. Some of thesedevices are centrifugal relying on a relative radial displacement forthe actuation of a clutch. This second type of inertial retractor iscalled "webbing sensitive" since the acceleration of rotation of thereel shaft is responsive to sudden withdrawal of webbing as occurs whenthe user is suddenly cast against the harness or webbing as in an impactaccident or sudden stop. In Europe it has been fairly common to combinethe function of these devices and such structures are reasonably wellrepresented in the U.S. art as in Kell U.S. Letters Pat. No. 3,905,562,in Stephenson U.S. Letters Pat. No. 3,858,824 and in Lindblad U.S.Letters Pat. No. 3,779,479. Simple and direct combinations of suchfeatures were seen also in the U.S. Letters Pat. No. 3,446,454 and3,489,367 to Kovacs et al.

The present invention goes beyond the prior art to achieve a positivelocking of the webbing drum against withdrawal of webbing in which agroup of concentric ratchets are interlocked drivably by a pilot pawlacted upon by a cam and the cam movement occurring because of therelative displacement between a flywheel or inertial rotating elementand a member driven by the drum. The displacement may also occur byholding or stopping the flywheel, as will be seen.

Another object is to achieve the above objective in a structure which iscompact as by miniaturization of the pendulum and nesting of elementsand wherein the entire mechanism for redundant locking actuationoccupies no more space than existing automatic locking retractormechanisms. This object is the consequence of reducing the forcenecessary from the sensors and the shielding of the sensing mechanismsfrom the ultimate lock stresses.

Still another object is to achieve redundant actuation in a positive andcoordinated manner in avoidance of pawl bounce either in the pilot pawlor the lock pawl so that relatively light resin materials may be usedthroughout the sensing mechanisms and only the lock pawl feels the lockup stresses of forces on the webbing transmitted through the drum andlock pawl and into the frame and thence to the vehicle.

Another object is to achieve synchronization of lock bar movement withthe drum ratchet so that the bar always enters the ratchet between teethunder positive drive in avoidance of chance bounce.

Other objectives including structural simplicity and integration ofcomplexes of parts with advantages in assembly and economic productionwill be appreciated by those skilled in the art as the descriptionproceeds.

GENERAL DESCRIPTION

The seat belt retractor or the present invention is a drum receptaclefor harness webbing and is used in vehicles for the comfort, protection,safety and convenience of the users of the vehicles, both drivers andpassengers. For example, the webbing or cable stored on the reel or drummay be withdrawn and coupled by buckles or other hardware to otherportions of harness to form selected shoulder and lap supports whichunder emergency conditions restrains the body of the user from beingprojected against the vehicle. The drum on which the webbing is wound isspring loaded or biased to rewind and the drum is provided with ratchetwheels. By blocking the ratchet wheels, as by a pawl, the withdrawal ofwebbing is prevented. The drum is fastened to a shaft and the shaft isconnected at one end to the coiled retractor spring or motor. The otherend of the shaft axially supports the lock-up mechanism comprising apair of concentric and nested ratchet elements functioning to lock indifferent directions and both free on the shaft. The two ratchets areselectively locked together when a pilot pawl intermediate the tworatchets is activated. The pawl is pivoted from the outermost of the twoconcentric ratchets (the flywheel) and is pivotal therefrom. A drivespider is connected to the shaft (hence turns with the shaft) andextends through the outer ratchet web. One leg of the spider is incamming relation to the pilot pawl element. The other leg of the spideris connected by a spring to the outer concentric ratchet. The outerconcentric ratchet is weighted in the manner of a flywheel and lostmotion slots in the web of the flywheel-ratchet allow relative movementbetween the spider or shaft and the flywheel. As relative displacementoccurs, the spider cams the pilot pawl outward into engagement with theinner nested ratchet and the motion causes positive drive of the innerratchet with the outer ratchet. The spring drags the flywheel aroundwith the spider and if acceleration of the shaft occurs, the spider runsahead of the flywheel and the camming of the pilot pawl occurs withconsequent driving of the concentric inner ratchet and this results inlimited rotation of the inner ratchet and projections extending radiallytherefrom and consequent tilting movement of a lock pawl bar intoblocking engagement with the ratchet flanges on the webbing spool ordrum. Since the number of teeth on the inner ratchet and the ratchetflanges of the drum are equal, the entry of the lock pawl bar to theratchet flange teeth is a drive entry and the pawl always enters betweenteeth in avoidance of pawl bounce by the selection of the tiltinggeometry of the lock bar moved by the inner ratchet. A relatively smallomnidirectionally sensitive pendulum is beneath the flywheel-ratchet.The pendulum element is a one-piece body in a resin case. Above the masscomprising the pendulum is a lever arm pivoted from the pendulum casewith a feeler tip extending vertically into an upper concavity in thependulum mass. As the mass shifts the lever is raised and it impinges onthe ratchet perimeter of the flywheel so that the flywheel is arrestedand relative displacement occurs as between flywheel and spider. Thedisplacement cams the pilot pawl outwardly blocking the inner ratchetand the movement of the drum causes rotating of the case of the innerratchet to move the lock pawl lever and the lock pawl. The lock pawl isbiased out of engagement with the ratchets on the drum by reason of alight spring. The arrangement or geometry of the teeth in the innerratchet and the ratchet flanges of the drum is such that the mechanicaland geometric consequence of movement of the inner ratchet tilts thelock pawl bar and it precisely enters the root or pocket between ratchetteeth and the motion of the lock pawl is thereupon a driven positivemotion imparted by the action of the retractor or drum in answer to thepull on the webbing. The teeth on the inner ratchet are directionallyopposed to the teeth on the ratchet flanges of the drum but are equal innumber.

No slip clutch structure is employed and as a consequence of thisconstruction, the pilot pawl, the inner ratchet, the outer ratchet(except for weighted web portion), the pendulum lever, and the pendulumcage, saddle and bearings are all of lightweight resin obeying thesmallest of forces and hence allowing reduction of the size of thependulum mass and consequent miniaturization. The locking force is apositive driving force camming from drum movement acting on the pawl barwhich positively seats the pawl at a frequency or speed to assure entrybetween the ratchet teeth. Suitable journalling is provided in supportof the shaft and to assure smooth and relatively friction-free movementof the drum and shaft in respect to the concentric inner and outerratchets. The device of the present invention allows reduction inweight, simplicity in construction and assembly, and excellentrepetitive accuracy.

IN THE DRAWINGS

FIG. 1 is a perspective view of a retractor in accord with the presentinvention in its relative installed position and with a cover over thelocking mechanism housing the redundant locking features.

FIG. 2 is a side elevation view of the retractor seen in FIG. 1 but withthe mechanism cover removed to illustrate the simplicity and compactnessof the mechanism and the miniaturization of the pendulum structure.

FIG. 3 is a front elevation view of the retractor structure of thepresent invention as seen in FIG. 2 with the mechanism cover removed andillustrating the nesting of concentric ratchet structures.

FIG. 4 is an enlarged expanded fragmental view of the pendulum cage andpendulum with pivotal latch in the tilt and untilt positions to stop themotion of the outer ratchet-flywheel against the very light spring dragof the spider thereby allowing the pivoted lever or latch to be madefrom injection molded resin and the pendulum cage to be similarlyprecision manufactured.

FIG. 5 is an exploded assembly related perspective view of the drumassembly, integral bearing saddle and cage, inner ratchet, lock pawllever, lock pawl bar, camming pawl, outer flywheel-ratchet, drivespider, bearing and springs.

FIG. 6 is a fragmented and enlarged partially cutaway view of theconcentric inner and outer ratchets as interrelated by the drive spiderkeyed on the shaft and camming the pilot pawl to engage the teeth of theinner ratchet. The relative location of the pendulum lever is indicatedin respect to the outer ratchet and the inner ratchet carries the lockpawl actuator lever dogs which tilt the lock pawl bar upon rotation ofthe inner ratchet.

FIG. 7 is a fragmental and partial end elevation view showing the lockpawl bar in the pawl bar lever and the post of the lever bracketed bythe actuator lever dogs which are moved with the inner ratchet to lockthe ratchet wheels of the drum in prevention of further webbingwithdrawal.

FIG. 8 is a full section front elevation view of the actuating mechanismof the present invention and fragmentally showing the frame, drum andratchet flange thereof and indicating the nesting of concentric ratchetsto keep the profile low.

SPECIFIC DESCRIPTION

Referring to the drawings and with first particularity to the FIG. 1thereof, a retractor 11, in accord with the present invention, is shownand oriented in its normal position of use in a vehicle (not shown). Theretractor 11 is redundant, locking against accelerated withdrawal ofbelt webbing or harness 12 from the drum 13 and locking when the vehicleimpacts or stops suddenly. The retractor 11 includes a rewind springmotor 14 which, as is well known in the art, applies a rewind or returnbias to the drum 13. Since the rewind motor 14 is well known, thedetails of its construction are felt unnecessary to a full appreciationof the present invention. The motor 14 usually comprises a flat coiledspring keyed at the inner end to the shaft of the drum 13 and supportedby the case or cover 15 and the frame 16 at the other end. The frame 16is channel shaped as shown and comprises the integral web floor 17 andleg portions 18 and 19. Between the legs 18 and 19 the drum or reel 13is supported or journalled. The drum 13 is connected (as will be seen)to a shaft and the harness belt or webbing 21 is wound thereon betweenthe ratchet wheel flanges 20 and 21. A resin protective cover 22 issecured over the sensor mechanism 23 which is located within the coveradjacent and outboard of the leg 18 of the frame 16.

In FIG. 2 the cover 22 has been removed and the sensor mechanism 23 isrevealed. Integral legs of the snap-bifurcated type or other fastenersnot a part of the present invention pass through the openings 24 throughthe frame leg 18 and may be integral or non-integral with the protectivecover 22 to secure the cover 22 in place. A lock pawl bar 25 extendsthrough the wall of the leg 18 and one of the end extensions of the pawlbar 25 is embraced by an actuating lever 26. The actuating lever 26 isplate-like with a drive dog rising transversely therefrom. The lever 26is keyed or configured to embrace the end of the lock bar pawl 25 andmovement of the lever 26 correspondingly tilts the lock bar pawl 25. Asthe lever 26 is moved, the pawl bar 25 is tilted. The spring 27 actingbetween frame 16 and bar 25 biases the pawl bar 25 and lever 26 to anunlocked position as will be seen. A journal saddle 28 integral with thependulum support cage 29 is located in a slot 30 in the leg 18 by thechannel flaps or flanges 31 and is supported from a journal portionembracing (as will be seen) the shaft 32. This support assuresdimensional indexing of the saddle 28 and consequently the cage 29. Thependulum mass 33 (erect in the vertical position) is nested in thependulum cage 29. The lever 34 on pivot 35 tilts in following engagementwith the top of the mass 33. The lever 34, cage 29 and saddle 28 are allprecision fabricated as by injection molding from plastic or resinmaterial selected for good mechanical strength, good dimensionalstability, good bearing quality, and low weight as for example,polypropylene or a resin sold by E. I. duPont de Nemours and Companyunder the trademark or tradename, Delrin.

The free tip of the lever 34 is aligned to engage, upon tilting, theteeth on outer ratchet wheel 36 and the outer ratchet wheel 36 issecured as by a friction fit (sufficient friction to exceed the strengthof spring 45) on the perimeter of the flywheel 37. Keyed or fastened tothe shaft 32 so as to be driven thereby is the drive spider 38 with legs39 and 40. The legs 39 and 40 extend through the arcuate clearanceopenings 41 and 42 transversely through the web 43 of theratchet-flywheel 36-37. The leg 39 of the drive spider 38 extends tocamming relation with a pilot pawl 44. The leg 40 is secured by thetension spring 45 to the ratchet-flywheel 36-37 so that as the beltwebbing or harness 12 is withdrawn as shown in FIG. 1, the spring 45urges the ratchet-flywheel 36-37 to follow the movement of the spider 38and if there is a sudden acceleration of the shaft 32 from acceleratedwithdrawal forces on the belt webbing 12, then the ratchet-flywheel36-37 lags behind the spider 38 and the leg 39 of the spider 38 movesrelative to the flywheel 37 (permitted by arcuate openings 42 and 43) asshown in a clockwise direction and urging the pilot pawl 44 radiallyoutward. As will be seen, this same phenomena is observable when thependulum following lever 34 arrests movement of the outer ratchet wheel36. These phenomena, as will be seen, result in a coordinated movementof the lock pawl bar 25. The web or floor 17 of the frame 16 includesmounting provisions for clamping or securing the retractor 11 to thestructural parts of the vehicle (not shown) so that the pendulum 33 isnormally erect in vertical position in the cage 29. As will beappreciated, the configuration of the frame 16 may be adjusted to suitparticular mounting problems and the webbing 12 can be trained oversuitable passages or bars to remote use orientation. The snap ring 46secures the assembly on the shaft 32 (as shown) from axial displacementand the pin 47, as will be seen, is a pivotal support for the pilot pawl44.

In FIG. 3 the structure of FIG. 2 is best appreciated so that theminimal extension in an axial direction is appreciated as resulting in ahighly compact structure and the inner ratchet 50 is visiblesubstantially nested in the inboard perimeter of the outer ratchet 36.The mounting opening 51 through the floor or web 17 of the frame 16 isvisible and the pawl lock bar 25 is seen extending between the legs 18and 19 of the frame 16 to selectively and tiltably lock and block thewithdrawal rotation of the drum 13 at the ratchet wheel flanges 20 and21.

Referring to FIG. 4, the miniature pendulum structure can be bestappreciated. It is this pendulum structure 60 which renders thestructure of the present invention vehicle sensitive. The pendulum 33 isa metal high specific gravity mass such as brass, bronze, lead, iron orthe like and which has a conic concavity 61 at the top and which bellsoutwardly toward a base skirt 62 and the mass or pendulum 33 issymmetric on the vertical axis, as shown, unless displaced. The cage 29is of resin material such as a polypropylene which has an internalclearance allowing the tilting of the mass 33 off of the horizontal base63 at the end of the short stem 64. The base 63 is urged by the dishedconfiguration 65 of the bottom of the cage 29 to the vertical position.As shown by the phantom lines any sudden inertial imbalance as by abruptbraking or stopping causes the pendulum 33 to tilt in the cage 29 and indoing so effectively raises the effective center of the concavity 61 andraises the lever 34 on the pivot 35. The depending dimple or protrusion66 which is integral with the lever 34 rests in the concavity 61 and inthe vertical position of the pendulum mass 33, the dimple 66 rests onthe axis of the mass. As the mass 33 tilts from omnidirectionalimbalance of inertial forces such as a sudden application of brakes, thelever 34 pivots as the dimple 66 follows the upward motion of the conicwall of the concavity 61. As the lever 34 raises it engages the outerratchet 36 of the ratchet-flywheel 36-37 and arrests its rotationthereby achieving a relative movement between the spider 38 or shaft 32and the flywheel 37. As will be seen, this relative motion moves thepilot pawl 44 in the inner ratchet and pivoted on the pin 47 (in opening76 of pilot pawl 44) of the outer ratchet to result in ultimate andcoordinated blocking or locking of the pawl bar 25 against the teeth ofthe ratchet wheels 20 and 21 of the drum 13 and in prevention of thefurther withdrawal of harness webbing 12.

In FIG. 5 the assembly relationship is best comprehended and the innerratchet 50 is best appreciated to achieve by limited movement thetilting of the pawl bar 25 by the positive rotating displacement of thelever 26 by the spaced-apart radial extensions 68 from the base or web69 of the inner ratchet structure 50. Hence, as the inner ratchet 50rotates, the radial extensions 68 rotate and embrace between them thedrive dog 70 of the lever 26. The position of the radial extensions 68astraddle the drive dog 70 is selected so that movement of the innerratchet 50 obeys the rotation of the drum 13 and the pawl bar 25 engagesthe ratchets 20 and 21 between the teeth thereof. In general, the innerratchet 50 is cup shaped as shown and is free at the bearing 71 on theshaft 32. The disc shaped base 69 is surrounded by an integral flange 72which includes the integral ratchet teeth 73 geometrically opposite tothe sense of the teeth in outer ratchet 36 and the ratchet flanges 20and 21 on the drum 13. The pawl 44 impinges on the teeth 73 in the innerratchet 50 under the inertial influence of accelerated webbingwithdrawal or vehicle sensing of inertial imbalance imparted to the pawl44 by relative differential movement between the outer ratchet 36 andthe spider 38 driven by the shaft 32. The number of teeth in the innerratchet 50 equals the number of teeth in each of the ratchet flanges 20and 21 of the drum 13. In the units tested, 15 and 16 tooth ratchetswere employed with good results. The spring 27 is attached at end 74 tothe leg 18 of the frame 16 (FIG. 7) and the end 75 is connected to thepawl bar 25 at the opening 67 therethrough. This biases the lock pawlbar 25 to a position out of engagement with the ratchet wheel flanges 21and 20 of the drum 13 and provides sufficient minimal resistance to anyfrictional tendencies of the inner ratchet 50 to move. This is becausethe dog 70 on the lever 26 is held in the pawl bar 25 inactive position.The inner ratchet 50 nests in a perimeter groove in the flywheel-ratchet37-36 structure and the pilot pawl 44 is pivotally supported on the pin47 in a cavity between the inner and outer ratchets 50 and 36,respectively. The opening 76 provides an easy running fit on theprojection of the pin 47 and the movement of the pilot pawl 44 on thepin 47 gives the tooth 77 a sufficient travel to block the ratchet teeth73 of the inner ratchet 50. However, the movement of the pawl 44 on thepin 47 is determined by the camming action of the leg 39 of the drivespider 38 which extends through the ramped cam slot 78 in the pilot pawl44. The leg 39 of spider 38 thus imparts a positive cam drive force tothe pilot pawl 44 when relative separation occurs between the speed ofthe spider 38 and the flywheel-ratchet 37-36. This occurs when thependulum lever 34 is elevated by sensed inertial imbalance to engage andarrest the outer ratchet 36 and when sudden acceleration of the shaft 32drives the spider 38 ahead of the flywheel 37. The grommet bearing 79rests on the shaft 32 and supports the free running flywheel 37 on theshaft 32 and separates the drive spider 38 from frictional drag on theflywheel 37. Thus the spider 38 on withdrawal of webbing 12 from thedrum 13 pulls the flywheel 37 with it by means of the energy storingspring 45 secured at opening 80 to the flywheel 37 and to the leg 40 ofthe spider 38. The pawl bar 25 is of flat metal and is poised on theframe 16 at the tab extensions 81 and 82 in arcuate slots (not shown) inthe legs 18 and 19 so as to allow the pawl teeth 83 to tilt into and outof ratchet engagement with the registering wheels 20 and 21 of the drum13.

In FIG. 6 the nesting of the outer ratchet 36 and flywheel 37 to enclosethe inner ratchet 50 and the functioning of the positive drive mechanism23 in coordination with two sensed inertial forces is best appreciated.The pendulum lever 34 is seen to be displaceable to arrest motion of theflywheel-ratchet 37-36 and when the drive spider 38 is moving with theshaft 32, the spring 45 is elongated and the leg 39 of the spider 38 isrotated and the leg 39 in the diagonal slot 78 cams the pawl 44outwardly as previously described to engage and drive the inner ratchet50 in a clockwise direction with the spider 38 as shown, thus rotatingthe lever moving extensions 68 of the inner ratchet 50 and locking thewebbing 12 against withdrawal when the pawl bar engages the ratchetwheels 20 and 21 of the drum 13. The extensions 68 as previouslydescribed assure timing of the entry of the pawl lock bar 25 between theteeth of the ratchet flanges 20 and 21. The camming action in the slot78 of the pilot pawl 44 is clearly seen and the consequent displacementof the pilot pawl is shown in phantomline. The same camming occurs whenthere is a sudden accelerated withdrawal of webbing because then thespider 38 leads the trailing flywheel 37.

By reference to FIG. 7 the consequence of clockwise rotation of theinner ratchet 50 is best expressed since the inner ratchet 50 moves thedog 70 by reason of the corresponding movement of the radial extensions68 and this tilts the plate-like lever 26 and the firmly grasped pawlbar 25 against the light return bias of the spring 27.

In the FIG. 8, by enlargement, the compactness of this redundantpositive drive inertial retractor mechanism 23 is best appreciated withits miniaturized pendulum structure 33 in support cage 29 and theupstanding arm 85 of the saddle 28 is shown best with the integralbearing portion 86 on the shaft 32 in journalling relation and with theflanges 31 in support of the integral cage 29 by sandwich impingement onthe leg 18 of the frame 16.

As shown, no resistance is imposed to retraction of webbing 12 by themotor 14. The pawls 44, 25 and the lever 34 are disabled in preventionof retraction unless, of course, there is tension in the webbing 12.When retraction occurs and tension on the webbing 12 is relieved, thesprings 27 and 45 bias the structure to normalcy when the lever 34 isallowed to return by the restoration of verticality in the pendulum 33.The structure thus described is adjustable in sensitivity and thestructure functions well under extended testing which subjects thestructure to alternating vehicular sensed inertial imbalance andaccelerated webbing withdrawal. The extensive use of resin parts hasgreatly reduced bulk. The use of resin in previously inertia sensitivelevers and pawls provides assurances against false sensing by the partsthemselves avoiding inertial forces by reduction in specific gravity.This also reduces the force required to sensitize the system and allowsvery small pendulum masses and consequent miniaturization. The use ofthe pilot pawl and the geometry of the ratchets to each other and themovement of one ratchet to impart lock forces assures a positive driveand proper pawl to tooth entry in the structure. All of this inreference to a pawl bar lock-up results in a superior and simplerredundant locking inertial retractor as can be appreciated by thoseskilled in the art.

Having thus described an operative preferred embodiment of theinvention, those skilled in the art will readily perceive obviouschanges, modifications, and improvements therein within the spirit ofthe invention and such changes, modifications and improvements areintended to be included herein limited only by the scope of thehereinafter appended claims.

I claim:
 1. An inertial retractor mechanism for safety belt webbing,having a bias to rewind, the structure for drivably locking saidretractor against withdrawal comprising:a frame; a webbing drum havingratchet end flanges journalled in said frame; a lock bar pawl in saidframe in tiltable lock relation to said ratchet end flanges; a flywheelhaving a clearance opening and a recess; a pilot pawl pivoted on saidflywheel and including a positive drive connection to said drum throughsaid clearance opening in said flywheel; an inner faced ratchet inindependent rotational relation to said flywheel located in said recessof said flywheel and coaxial therewith, said inner faced ratchetincluding drive projections connected to said lock bar and said innerfaced ratchet in engageable register with said pilot pawl, said innerfaced ratchet having an equal number of teeth to the teeth on saidratchet end flanges of said drum; means resiliently connecting saidflywheel to said drum for rotation therewith whereby upon lagging inrotation of said flywheel relative to said drum, said pilot pawl isdriven by said positive drive connection into engagement with said innerfaced ratchet, and said lock pawl bar is tilted, by rotation of saidinner faced ratchet, into locking engagement with said ratchet endflanges.
 2. In the combination of claim 1 wherein a cam provides saidpositive drive connection between said drum and said pilot pawl.
 3. Inthe combination of claim 2 wherein said flywheel includes an outer facedratchet and wherein a pendulum means is positioned beneath said flywheelin registrable engageable lock relation with said flywheel ratchet. 4.An inertial retractor mechanism, having a bias to rewind, the structurefor drivably locking said retractor against withdrawal comprising:aframe; a retractor drum having ratchet flanges rotatable in said frame;a lock bar pawl in said frame biased against engagement with saidratchet flanges and tiltable toward engagement with said ratchetflanges; an inner faced ratchet engageable with said lock bar pawl andhaving oppositely oriented teeth from said ratchet flanges on said drum;a pilot pawl pivotally moveable toward and away from lock engagementwith said inner faced ratchet; a drive spider concentric with said drumand said inner ratchet and having a drive dog in camming relation tosaid pilot pawl and drivably connected to said drum; a flywheelresiliently connected to said drive spider and in which said spider isnested and said inner faced ratchet is concentrically positioned, saidspider driven by said drum and said spider resiliently driving saidflywheel and said pilot pawl, upon accelerated withdrawal of webbingfrom said drum, and said pawl thereupon drivably engaging said innerfaced ratchet; and a pendulum positioned adjacent said flywheel andselectively moveable by inertial forces to engage said flywheel,delaying rotation of said flywheel, whereby said spider moves said pawland said pawl engages said inner faced ratchet locking said drum bytilting said pawl bar into engagement with said ratchet flange of saiddrum.
 5. In the combination set out in claim 4 wherein said pendulum issuspended in a saddle and cage structure; andjournal supports integrallyextending from said saddle and cage structure in support of said drumand secured to said frame against lateral and rotational displacement.6. In the combination of claim 4 wherein said inner faced ratchetincludes a pair of spaced-apart radial projections, said projectionsfrom said inner faced ratchet drivably connected to said lock bar pawlwhereby movement of said inner faced ratchet moves said lock bar pawl tolockably engage said ratchet flange of said drum.
 7. In the combinationof claim 4 and including a pair of spaced-apart radial projectionsdrivably connected to said lock bar pawl and the teeth on said innerratchet are equal in number to the teeth in said ratchet flanges of saiddrum and said radial projections are positioned to positively drive saidlock bar pawl between adjacent of said teeth on said ratchet flanges. 8.An inertial retractor for safety belt webbing, having a bias to rewind,the structure for drivably locking said retractor against withdrawalcomprising:a frame; a retractor drum biased to rewind safety beltwebbing thereon and including a pair of matched spaced-apart ratchetflanges; a shaft axially secured to said drum and rotatable therewithand journalled in said frame; a drive spider secured to one end of saidshaft and rotating with said shaft; a flywheel freely rotatable on saidshaft and having an outer ratchet face, a pair of arcuate openingstherethrough and a pivot pin through said flywheel in an axis paralleland offset from said shaft; a spring connecting said flywheel drivablyto said spider; a pilot pawl pivotally mounted on said pilot pin andincluding a cam slot engaged with said spider; an inner faced ratchetmember free on said shaft and having internal teeth in opposed directionto said flywheel outer ratchet and said ratchet flanges on said drum andin concentric relation within said flywheel and said pilot pawl on saidflywheel in engageable register with said internal teeth and said innerfaced ratchet member including a pair of spaced-apart radialprojections; a saddle element having a journal portion embracing saidshaft, a pair of spaced-apart integral frame supporting and positionorienting flanges, and an integral cage portion; a lever pivotallysupported by said cage portion; a pendulum mass supported by said saddleand in said cage portion of said saddle, said pendulum mass in followingengagement with said lever; a pawl lock bar in said frame and intiltable locking register with said ratchet flanges and biased out ofcontact with said flanges; and a drive dog operably connected to saidpawl lock bar and extending between said radial projections from saidinner faced ratchet member whereby movement of said inner faced ratchetmember by cam activation of said pilot pawl causes locking of said drumagainst withdrawal of said webbing therefrom.
 9. An inertial retractorfor safety belt webbing, having a bias to rewind, a webbing drum withratchet flanges in a support frame, and lock bar tiltable on said frametoward and away from said ratchet flanges, the structure for drivablylocking said retractor against withdrawal comprising:a drive spiderdrivably connected to said drum and having legs; a flywheel rotatable onthe axis of said drum and resiliently drivable by said spider in awithdrawal rotation of said drum and axially and internally engaged withsaid spider on one side, said flywheel having a pivotal supportextending to the other side and said flywheel having a pair of arcuateslots therethrough whereby said leg extensions of said spider projectand said flywheel having a perimeter ratchet surface; a pilot pawlpivotally connected to said flywheel at said pivotal support of saidflywheel, said pilot pawl including a cam slot through which one of saidlegs of said drive spider is connected; resilient means connecting saidother of said legs of said spider with said flywheel; an inner facedratchet element coaxially in said flywheel and enclosing said pilotpawl, said pilot pawl pivotal to engage said inner faced ratchet elementand said inner faced ratchet element including a pair of spaced-apartradial projections, said projections operably embracing said lock pawlbar and upon movement of said inner faced ratchet element underwithdrawal of said webbing, said lock pawl bar is urged toward saidratchet flanges of said drum; and pendulum inertial means secured tosaid frame and extendable to arrest said flywheel in the withdrawaldirection of rotation.